JP6217712B2 - Liquid paper container - Google Patents

Description

  The present invention relates to a liquid paper container. In particular, the present invention relates to a liquid paper container that can be easily disassembled.

  Liquid paper containers used for liquid contents such as foods and non-foods are widely used, with milk as a typical example, and are laminated with a sealant layer made of thermoplastic resin on the inner surface of paper. Made of material. Liquid paper containers are also widely used for liquid foods such as fruit juice drinks, juice, tea, coffee, milk drinks, soups, and other liquors such as sake and shochu.

  These liquid paper containers are composed of a paper base material and a sealant layer, and a gas barrier layer using an aluminum foil, a metal vapor deposition film, a metal oxide vapor deposition film, etc. between the paper layer and the sealant layer, or In some cases, a layer having a gas barrier property such as an inorganic compound vapor-deposited film is provided.

  Paper containers are widely used because of their convenience and economy, and are widely used as packaging containers for various products. In recent years, from the viewpoint of environmental conservation, volume reduction when containers are disposed of has been demanded, and a recycling system for reuse as a resource has been established. There is also a change. Under such circumstances, for example, milk cartons that have been used are dismantled on the consumer side for recycling and placed on a separate collection route. In addition, dismantling, reducing the volume and disposing of containers that are not on the separate collection route are becoming established.

  However, there are problems when actually dismantling. For example, there is a liquid paper container with a cap on the roof plate at the top of the gable roof shape, but since the cap is firmly welded, the top can be separated to be discarded for disposal. It was difficult except for opening the seal part and cutting around the plug with scissors.

  Furthermore, since the above-described conventional liquid paper container is firmly sealed by heat-sealing the top seal portion, when disassembling the empty container after use, the top seal portion is manually opened to disassemble the container. There were things that were difficult.

  This is because the top seal portion of the liquid paper container is sealed in a state where the folded laminated body is in contact with it, so that a gap is likely to be formed. Therefore, the sealant layer on the back surface of the liquid paper container has fluidity at the time of melting. This is because a good polyethylene resin is used, and sealing is performed at a high temperature and a strong pressure so as to fill a gap and complete sealing.

  Against this backdrop, the seal strength has become stronger. Therefore, if the sealing temperature is lowered or the pressure is weakened in order to weaken the sealing strength, there is a risk that the sealing becomes incomplete and liquid leakage occurs.

  Alternatively, it is possible to disassemble the empty container by cutting with a pair of scissors instead of opening the top seal, but it is quite possible to cut a hard plug or its periphery with scissors. The methods that are difficult and require tools are cumbersome and are not in common practice.

As an improvement of this situation, there is a liquid paper container in which the side plate of the body portion is cut off so that it can be easily disassembled as a trigger.

  For example, in the method described in Patent Document 1, both ends of a composite sheet in which a synthetic resin layer is provided on the front and back of a paper layer are overlapped with each other, and the composite sheet on the outer surface side in which the sealed body part is overlapped. A pull tab is provided at the end, and the pull tab is a liquid paper container provided so as to be peelable through a peelable layer made of an easily peelable tape-like film. This tape-like film is provided continuously along the inner surface of the four side plates, and along the both edges in the width direction of the tape-like film, a cut line, a half cut, a perforation, etc. in the paper layer of the composite sheet The cutting line is engraved.

  However, in the liquid paper container proposed here, an easily peelable tape-like film is necessary, and the seal of the body part bonding portion may become unstable due to the easily peelable tape-like film. Therefore, further improvement or simplification of disassembly by another method is desired for disassembly after use of the container.

Japanese Patent No. 3844310

  The present invention has been made in view of such a situation, and in a liquid paper container based on a paper base material, it is an object to provide a liquid paper container having a simple container structure and easy disassembly after use. And

As a means for solving the above problems, the invention according to claim 1 is a liquid paper comprising a laminate having a thermoplastic resin layer on the container outer layer side of the paper substrate and a sealant layer on the container inner layer side. A liquid paper container characterized in that a linear fragile part for bending and dismantling is formed in the body part of the container, and the moisture content of the paper base material is less than 8%.

  The invention according to claim 2 is the liquid paper container according to claim 1, wherein the weakened portion for disassembling is due to scratching provided on the paper base material. .

  The invention described in claim 3 is characterized in that the scratch processing provided on the paper base is formed by laser beam processing or half-cutting processing or full-cutting processing using a blade shape. Item 3. A liquid paper container according to Item 2.

  According to a fourth aspect of the present invention, the laminate has an intermediate layer between the paper base material and the sealant layer, and the intermediate layer is a gas barrier layer in which an inorganic compound layer is provided on a plastic film. The liquid paper container according to claim 1, further comprising:

  The invention according to claim 5 is characterized in that the laminate has an intermediate layer between a paper base material and a sealant layer, and the intermediate layer has a gas barrier layer made of a metal foil. The liquid paper container according to claim 1.

  The invention according to claim 6 is based on the flaw processing provided in the gas barrier layer in which the weakened portion for dismantling is provided on the paper base material and the same position as the flaw processing. 6. The liquid paper container according to claim 4, wherein the liquid paper container is provided.

  Further, the invention described in claim 7 is characterized in that the scratch processing provided on the paper base is formed by laser beam processing, half punching using a blade shape, or full punching. A liquid paper container according to claim 6.

  The invention described in claim 8 is characterized in that the flaw processing provided in the gas barrier layer is formed by laser beam processing, half punching using a blade shape, or full punching. The liquid paper container according to Item 6 or Claim 7.

  ADVANTAGE OF THE INVENTION According to this invention, in the liquid paper container based on a paper base material, it is possible to provide the liquid paper container which has a simple container structure and can be easily disassembled after use.

  According to the invention described in claim 2, it is possible to provide a liquid paper container that can be easily disassembled.

  According to the invention described in claim 3, it is possible to provide a liquid paper container that can be easily and stably disassembled.

  According to the invention described in claim 4, it is possible to provide a liquid paper container that can be used in a wider range and can be easily disassembled.

  According to the invention described in claim 5, it is possible to provide a liquid paper container that can be used in a wider range and can be easily disassembled.

  According to the sixth aspect of the present invention, it is possible to provide a liquid paper container that can be used in a wider range and can be easily disassembled.

  According to the seventh aspect of the invention, it is possible to provide a liquid paper container that can be used in a wider range and can be easily and stably disassembled.

  According to the eighth aspect of the present invention, it is possible to provide a liquid paper container that can be used in a wider range and can be easily and stably disassembled.

FIG. 1 is a partial cross-sectional schematic view for explaining an embodiment of a laminate used for a liquid paper container according to the present invention. FIG. 2 is a partial cross-sectional schematic view for explaining another embodiment of the laminate used in the liquid paper container according to the present invention. FIG. 3 is a schematic perspective view showing an embodiment of a liquid paper container according to the present invention. FIG. 4 is a plan development view of an embodiment of a liquid paper container according to the present invention.

  Hereinafter, a detailed description will be given of embodiments for carrying out the invention with reference to the drawings. However, the present invention is not limited only to these examples.

  FIG. 1 is a partial cross-sectional schematic view for explaining an embodiment of a laminate used for a liquid paper container according to the present invention. The laminate (100) uses paper as a base material, has a paper base material (1), and has a sealant layer (2) on the container inner layer side through an adhesive layer (3). A thermoplastic resin layer (4) is provided on the container outer layer side of the paper substrate, and a printing layer (5) is provided on the outermost layer.

  In the present invention, a fragile portion is provided in the paper base material for disassembling the container after using the liquid container, and the fragile portion is composed of a scratch processing portion (6) from the container outer layer side of the laminate to the paper base material. . Dismantling can be performed by bending and cutting the fragile portion, and cutting and separating the laminate with the scratched portion (6) as a trigger. In the present invention, paper having a moisture content of less than 9% is used for the paper substrate (1).

  FIG. 2 is a partial cross-sectional schematic view for explaining another embodiment of the laminate used in the liquid paper container according to the present invention. In the embodiment example of the laminate (100) shown here, the paper substrate is bonded to the gas barrier layer (10) via the adhesive layer (7), and the gas barrier layer (10) is a plastic film layer (8). And an inorganic compound layer (9). A sealant layer (2) is provided on the container inner layer side of the laminate through an adhesive layer (3).

  A thermoplastic resin layer (4) is provided on the container outer layer side of the paper substrate (1), and a printed layer (5) is provided on the outermost layer. In the embodiment example shown here, the fragile part is located at the scratched part (6) from the container outer layer side to the paper substrate (1) and the scratched part (11) provided on the gas barrier layer (10). Are provided in the same manner. Disassembling can be performed by bending and cutting the fragile portion, and cutting and separating the laminate using the scratched portion (6) and the scratched portion (11) as a trigger. In the present invention, paper having a moisture content of less than 9% is used for the paper substrate (1).

  FIG. 3 is a schematic perspective view showing an embodiment of a liquid paper container according to the present invention. The liquid paper container (101) shown in this embodiment is called a Gobeltop paper container used for liquids such as milk, and includes a top part (23), a trunk part (22), and a bottom part (24). The top portion (23) has a roof-shaped slope with the top seal portion (21) at the top, and a spigot (20) for pouring out the contents is attached.

  FIG. 4 is a plan development view of an embodiment of a liquid paper container according to the present invention. This is a plan development view of the liquid paper container of the embodiment shown in FIG. In order to assemble the liquid container, a quadrangular column of the body (22) is formed using the sticking plate (25) and the crease line (27), and the top (23) and bottom ( 24). Although the weak part is provided in the trunk part, the top part (23) and the trunk part (22) can be easily cut and separated by providing the weak part (26) by, for example, scratching.

  Hereinafter, each component constituting the liquid paper container according to the present invention will be individually described in detail with reference to the drawings.

  In the liquid paper container according to the present invention, paper having a moisture content of less than 9% is used for the paper substrate (1). This is what we have found in the process of diligently examining the configuration of a liquid paper substrate that can be easily disassembled. By using a paper base in this range, the scratched portion constituting the fragile portion is subjected to a force such as bending, so that the scratched portion is damaged, and the laminate is cut and separated to remove the liquid paper container. It can be easily dismantled. The moisture content can be measured using a heat drying moisture meter.

  When the moisture content is higher than the range according to the present invention, the scratched portion cannot be sufficiently damaged, and it is difficult to realize easy disassembly. This is considered to be due to the fact that when the moisture content is high, the paper stretches and the scratched portion cannot be sufficiently damaged. In addition, when the moisture content of the paper is high, there is a risk of inducing pinholes due to evaporation of internal moisture by heating with hot air in the assembly after assembling or filling the liquid paper container.

  On the other hand, if the moisture content of the paper is low, for example, less than 5%, disassembly is satisfactory, but the paper does not stretch, and there is a risk of cracking or tearing the paper at the fold line assembly. Therefore, the moisture content is desirably 5% or more. Therefore, the moisture content of the paper base paper according to the present invention is in the range of less than 9%, more preferably in the range of 5% or more and less than 8%.

  In the present invention, the moisture content of the paper hardly changes even after the paper container manufacturing process, filling, and sealing process because the laminated material is sandwiched between the thermoplastic resin layer and the sealant layer. By using paper having a moisture content of less than 9% as the material of the laminate, a liquid paper container that can be easily disassembled after use can be obtained.

Although it does not specifically limit as a paper base material (1), Generally board | boards, such as a milk carton base paper, are used. The basis weight and density are appropriately selected depending on the capacity and design of the container. Usually, paper having a basis weight of 200 to 500 g / m ² and a density of 0.6 to 1.1 g / cm ³ is preferably used.

  The fragile portion can be formed by providing a scratched portion (6) from the container outer layer side of the laminate (100) to the paper substrate (1). When the gas barrier layer is included in the laminate, the flawed portion (11) can be formed in the gas barrier layer at the same position so as to be a weak portion of the laminate.

  The scratch processing provided on the paper substrate (1) can be formed by laser beam processing, half punching using a blade shape, or full punching. When the laminate includes a gas barrier layer, the fragile portion is constituted by a scratch processing provided on the gas barrier layer in the same position as the scratch processing on the paper substrate. The scratch processing provided in the gas barrier layer can be formed by laser beam processing, half punching using a blade shape, or full punching.

  The fragile portion is provided in the body portion (22) of the liquid paper container (101), but the position is not limited. However, for example, when it is provided at the boundary between the body part and the top part, it also overlaps with the crease line, so that after use of the container, the container is folded at the crease line to damage the fragile part, and work efficiency is improved when cutting and separating. In addition to being good, the top part to which plastic parts such as plugs are attached can be easily cut off, which is also convenient and convenient for the purpose of dismantling such as recycling.

  A sealant layer (2) is provided on the layer of the laminate (100) on the inner side of the container. With the sealant layer, the laminate can form a three-dimensional box shape, and the container can be sealed after filling the contents. Generally, a polyolefin resin is used for the sealant layer.

  Specific examples of the polyolefin resin include low density polyethylene resin (LDPE), medium density polyethylene resin (MDPE), linear low density polyethylene resin (LLDPE), ethylene-vinyl acetate copolymer (EVA), and ethylene-α. Ethylene resins such as olefin copolymer, ethylene-methacrylic acid resin copolymer, blend resin of polyethylene and polybutene, homopolypropylene resin (PP), propylene-ethylene random copolymer, propylene-ethylene block copolymer Polypropylene resins such as coalesced and propylene-α olefin copolymers can be used.

An adhesive layer (3) can be provided between the sealant layer (2) and the gas barrier layer (10), or between the sealant layer (2) and the paper substrate (1). The adhesive layer may be an extruded resin layer or may be a laminating adhesive. As the resin used for the extruded resin layer, a thermoplastic resin such as a polyethylene resin can be used. The thickness is usually in the range of 5 μm to 20 μm. When a laminating adhesive is used, a urethane two-component curable dry laminating adhesive (including a solventless adhesive) can be used. The dry coating amount is preferably 0.5 to 7.0 g / m ² .

  For the purpose of improving the storage stability of the contents, an opaque layer such as a colored film for shielding ultraviolet rays can be provided in the laminate. Alternatively, a gas barrier layer can be provided in the laminate.

  The gas barrier layer (10) can be used as a gas barrier layer by providing a metal foil such as an aluminum foil or a vapor deposition layer of a metal or an inorganic compound on a plastic film. Inorganic compounds include inorganic compounds such as SiO and AlO. The gas barrier layer can be laminated using an adhesive, for example, using a dry lamination method, or can be laminated by extruding a thermoplastic resin using an extruder.

  When the gas barrier layer is a gas barrier film, it can be formed by providing a vapor deposition layer and a coating layer of an inorganic compound on a plastic film. After providing an anchor coat on the plastic film, the vapor deposition layer and the coating layer are sequentially provided.

  As the plastic film used for the gas barrier film, a film of polyethylene terephthalate, nylon, polypropylene or the like can be used. In particular, a biaxially stretched polyethylene terephthalate film is preferably used because it has little expansion and contraction during vapor deposition and bonding. A thickness of 6 to 25 μm is preferably used.

  For example, urethane acrylate can be used for the anchor coat layer of the gas barrier layer. For the formation of the anchor coat layer, a coating method using a printing technique such as gravure coating with a paint in which a resin is dissolved in a solvent can be used, and a coating film can be formed using a generally known coating method.

  As a method for forming the vapor deposition layer, for example, an inorganic compound layer such as SiO or AlO can be formed on the base film provided with the anchor coat layer using a vacuum vapor deposition method. Furthermore, a coating layer of an inorganic compound can be stacked.

  As a method of forming a coating layer of an inorganic compound, an aqueous solution containing at least one of water-soluble polymer and (a) one or more alkoxides or hydrolysates thereof, or (b) tin chloride, or A coating agent mainly composed of a water / alcohol mixed aqueous solution is applied on a film and dried by heating to form an inorganic compound layer by a coating method to form a coating layer. At this time, the adhesion with the anchor coat layer can be improved by adding a silane monomer to the coating agent.

  The inorganic compound layer has a gas barrier property only by forming a vapor deposition layer by a vacuum vapor deposition method, but can be formed as a gas barrier layer by forming an inorganic compound coating layer on the vapor deposition layer by a vacuum vapor deposition method.

  By combining these two layers, a reaction layer of both layers is formed at the interface between the inorganic compound layer by the vacuum deposition method and the inorganic compound layer by the coating method, or the inorganic compound layer by the coating method becomes an inorganic compound layer by the vacuum deposition method. A dense structure is formed by filling and reinforcing defects such as pinholes, cracks, and grain boundaries, or by reinforcing them, so that high gas barrier properties, moisture resistance, and water resistance are achieved, and flexibility that can withstand deformation is achieved. Therefore, it can also be suitable as a packaging material.

In addition, when SiO is used as the inorganic compound layer, a metal detector or the like can be used as an inspection device, unlike when a metal foil is used as a gas barrier layer. These may be selected appropriately according to the use of the packaging bag and the required quality.

  The adhesive layer (7) is an adhesive layer for adhering the paper substrate (1) and the gas barrier layer (10). For example, you may laminate | stack by sandwich lamination using polyolefin resin. In this case, the thickness is usually in the range of 10 μm to 60 μm. If it is less than 10 μm, sufficient adhesive strength cannot be obtained.

  Specifically, ethylene resins such as low-density polyethylene and linear low-density polyethylene, polypropylene, or ethylene / α, β such as ethylene / acrylic acid copolymer or ethylene / methacrylic acid copolymer (EMAA). Unsaturated carboxylic acid copolymer, esterified product of ethylene / α, β unsaturated carboxylic acid copolymer such as ethylene / methyl acrylate, ethylene / ethyl acrylate, ethylene / methyl methacrylate, ethylene / ethyl methacrylate, Ionic cross-linked products of ethylene / α, β unsaturated carboxylic acid copolymers, ethylene / maleic anhydride graft copolymers, ethylene / ethyl acrylate / maleic anhydride, acid sites cross-linked with sodium ions or zinc ions Acid anhydride-modified polyolefins typified by terpolymers such as Epoxy compound-modified polyolefins, such as down-glycidyl methacrylate copolymer, a single resin selected from ethylene-vinyl acetate copolymer, or provided by such a mixture of two or more selected from these.

  In order to increase the adhesive strength, easy adhesion treatment such as corona treatment, ozone treatment, and anchor coating can be performed on the surface of the paper substrate or gas barrier layer.

  As the resin used for the thermoplastic resin layer (4) on the container outer layer side, a thermoplastic resin such as a low-density polyethylene resin or a linear low-density polyethylene resin can be preferably used. The thermoplastic resin layer (4) can be provided by, for example, extrusion lamination on the outer surface of the paper substrate using these thermoplastic resins.

  For the printing layer (5) provided on the outer surface of the thermoplastic resin layer, a method such as gravure printing, offset printing, gravure offset printing method, flexographic printing method, ink jet printing method or the like can be used using a known ink. . In addition to information on contents, printing can display logo marks and the like, and images, examples of use, barcodes, and the like regarding contents can be displayed in characters and images. It is preferable that the surface of the thermoplastic resin layer is subjected to easy adhesion treatment such as corona treatment to enhance the adhesion with the printing layer. An overcoat layer may be provided on the printed layer to improve wear resistance.

  Thus, according to the present invention, it is possible to provide a liquid paper container based on a paper base material, which has a simple container structure and can be easily disassembled after use. Hereinafter, the present invention will be described more specifically with reference to examples.

<Example 1>
The laminate for the liquid paper container has the following configuration from the outside of the liquid paper container toward the inside of the container.
Print layer / thermoplastic resin layer: low density polyethylene (thickness 18 μm) / paper substrate: (400 g / m ² ) / adhesive layer: EMAA (thickness 30 μm) / gas barrier layer: alumina-deposited polyethylene terephthalate film, (thickness 12 μm) / sealant layer: linear low density polyethylene (thickness 60 μm)
Using this laminate, a fragile portion was formed in the same manner as the liquid paper container (101) shown in FIG. 4, and a liquid paper container having a capacity of 2000 ml was produced.

In the low-density polyethylene layer and the paper base material, a scratched portion as shown in FIG. 1 was formed by cutting a single half up to 3/4 of the thickness of the paper by blade cutting.
In addition, the gas barrier layer was aligned to form a single punched portion by processing with a laser beam. The laser beam is emitted from a carbon dioxide laser device with an irradiation output of 21 W and a processing speed of 150 m / min. Irradiation was performed under the following conditions.
Each part of this blank was glued and molded, and then a stopper was attached to make a liquid paper container.

At this time, the moisture content of the paper substrate was 5.3%.
The moisture content was measured by taking out a paper substrate from a liquid paper container and using a heat drying moisture meter. The measurement conditions are 200 ° C. and 5 minutes.

  Once the content liquid was injected and it was confirmed that no leakage occurred, the content liquid was poured and the packaging container was disassembled. In addition, the tear strength of the scratched part was measured.

<Example 2>
The same as Example 1 except that the moisture content of the paper substrate was 6.7%.

<Example 3>
The same as Example 1 except that the moisture content of the paper substrate was 7.8%.

<Example 4>
The same as Example 1 except that the moisture content of the paper substrate was 8.0%.

<Comparative Example 1>
The same as Example 1 except that the moisture content of the paper substrate was 9.6%.

<Comparative example 2>
The same as Example 1 except that the moisture content of the paper substrate was 10.2%.

<Evaluation items and evaluation methods>
(Tear strength)
After the wound processing part was bent by 180 degrees one reciprocation, it was measured at a pulling speed of 200 mm / min using a tensile testing machine.
(Ease of dismantling)
Based on sensory evaluation.
The evaluation criteria were as follows: ○: can be easily disassembled, ×: cannot be disassembled, Δ: disassembly was possible but not easy.

  The evaluation results are shown in Table 1.

  From the results shown in Table 1, it can be seen that the tear strength increases as the moisture content of the paper substrate increases. Also, from the ease of disassembly by sensory evaluation, it can be seen that disassembly is not possible when the moisture content exceeds 9%. Conversely, if it is less than 9%, it is shown that disassembly is easy.

  Therefore, according to the present invention, in a liquid paper container based on a paper base material, it is verified that it is possible to provide a liquid paper container having a simple container structure and easy disassembly after use. I was able to.

DESCRIPTION OF SYMBOLS 1 ... Paper base material 2 ... Sealant layer 3 ... Adhesive layer 4 ... Thermoplastic resin layer 5 ... Print layer 6 ... Scratched part 7 ... Adhesive layer 8 ... Plastic film 9 ... Inorganic compound layer 10 ... Gas barrier layer 11 ... Scratched part 20 ... Plug 21 ... Top seal part 22 ... Body part 23 ... Top part 24 ... Bottom 25 ... Adhering plate 26 ... Fragile part 27 ... Folded line 100 ... Laminate 101 ... Liquid paper container

Claims (8)

A thermoplastic resin layer on the container outer side of the paper substrate, a liquid packaging cartons made of laminate having a sealant layer formed on the container inner side, linear weakened portion for bending demolition container body A liquid paper container which is formed in a portion and has a moisture content of the paper base material of less than 8%.   The liquid paper container according to claim 1, wherein the weakened portion for dismantling is due to scratching provided on the paper base material.   The liquid paper container according to claim 2, wherein the scratch processing provided on the paper base is formed by laser beam processing, half punching using a blade shape, or full punching.   2. The laminate according to claim 1, wherein the laminate has an intermediate layer between the paper base material and the sealant layer, and the intermediate layer has a gas barrier layer formed by providing an inorganic compound layer on a plastic film. The liquid paper container as described.   2. The liquid paper container according to claim 1, wherein the laminate has an intermediate layer between the paper base and the sealant layer, and the intermediate layer has a gas barrier layer made of a metal foil.   The fragile portion for dismantling is due to flaw processing provided on the paper base material and flaw processing provided on the gas barrier layer having the same position as the flaw processing. Item 6. A liquid paper container according to Item 5.   The liquid paper container according to claim 6, wherein the scratch processing provided on the paper base is formed by laser beam processing, half punching using a blade shape, or full punching.   The liquid paper according to claim 6 or 7, wherein the scratch processing provided in the gas barrier layer is formed by laser beam processing, half punching using a blade shape, or full punching. container.